diff -Naur hp2xx-3.4.4.orig/sources/png.c hp2xx-3.4.4.new/sources/png.c
--- hp2xx-3.4.4.orig/sources/png.c	2014-06-26 17:30:18.661919903 +0200
+++ hp2xx-3.4.4.new/sources/png.c	2014-06-26 17:32:10.554634712 +0200
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "to_png.h"
+#include <zlib.h>
 #include <png.h>
 
 #define PDNCOL 256
@@ -36,7 +37,7 @@
 	}
 
 	/* set up error handlimg for libpng */
-	if (setjmp(png_ptr->jmpbuf)) {
+	if (setjmp(png_jmpbuf(png_ptr))) {
 		png_destroy_write_struct(&png_ptr, &info_ptr);
 		return;
 	}